GB1329791A - Spray drying devices for the production of powder eg milk powder - Google Patents

Abstract

1329791 Spray drying; cyclone separators NIRO ATOMIZER AS 11 Jan 1972 [19 Jan 1971] 1298/72 Headings B1B and B2P A solution or dispersion of solids, e.g. skimmed milk concentrate, is dried by spraying it by means of atomizer wheel 5 into hot air supplied to chamber 1 through inlet 4, the dried powder is discharged through gas-lock valve 3 while moist air containing entrained fine powder is drawn through guide blades 10 into cyclone separator 9 from which moist air is withdrawn through outlet 6 and blower 7 but the separated fine power is drawn, with some of the moist air, through aperture 11 to the drying zone adjacent the atomizer wheel. The underside of wheel 5 carries radial ribs 13 (Fig. 2, not shown) to increase the suctionaction on the fine powder. In order to intensify the extraction from the cyclone, compressed air is injected, through pipe 14. In Fig. 4 (not shown), the intake from the drying chamber into the cyclone faces upwardly, and the fine powder which separates at the bottom of the cyclone is conveyed to the atomizer wheel by compressed air introduced through a tangential pipe (25). In Fig. 5, moist air and entrained fine powder flows from the drying chamber into separator chamber 20 through tangential or spiral inlet 22. The air circulates around filling body 24 and the powder separates to the bottom of chamber 20, and is conveyed to the atomizer wheel through tube 21 by means of compressed air introduced tangentially into the bottom of the chamber. Air leaves chamber 20 through tangential or spiral outlet 23. Gas-lock valve 3 at the base of the drying chamber may be replaced by a device comprising baffle 31 (Fig. 8) and two powder collecting channels 32 associated with perforated plates (not shown) and cooling-air inlets 37.